package cn.itcast.hotel.service.impl;

import cn.itcast.hotel.mapper.HotelMapper;
import cn.itcast.hotel.pojo.Hotel;
import cn.itcast.hotel.pojo.HotelDoc;
import cn.itcast.hotel.pojo.RequestParams;
import cn.itcast.hotel.result.PageResult;
import cn.itcast.hotel.service.IHotelService;
import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import lombok.extern.slf4j.Slf4j;
import org.elasticsearch.action.search.SearchRequest;
import org.elasticsearch.action.search.SearchResponse;
import org.elasticsearch.client.RequestOptions;
import org.elasticsearch.client.RestHighLevelClient;
import org.elasticsearch.common.geo.GeoPoint;
import org.elasticsearch.common.unit.DistanceUnit;
import org.elasticsearch.index.query.BoolQueryBuilder;
import org.elasticsearch.index.query.QueryBuilders;
import org.elasticsearch.index.query.functionscore.FunctionScoreQueryBuilder;
import org.elasticsearch.index.query.functionscore.ScoreFunctionBuilders;
import org.elasticsearch.search.SearchHit;
import org.elasticsearch.search.SearchHits;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightBuilder;
import org.elasticsearch.search.fetch.subphase.highlight.HighlightField;
import org.elasticsearch.search.sort.SortBuilders;
import org.elasticsearch.search.sort.SortOrder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;

/**
 *
 * 搜索框搜索
 *
 * */
@Slf4j
@Service
public class HotelServiceImpl extends ServiceImpl<HotelMapper, Hotel> implements IHotelService {


    @Autowired
    private RestHighLevelClient client;

    /**
     * 根据关键字搜索酒店信息
     * @param params 请求参数对象，包含用户输入的关键字
     * @return 酒店文档列表
     */
    @Override
    public PageResult search(RequestParams params) {
        try{
            //1.准备request
            SearchRequest request = new SearchRequest("hotel");
            //2.准备DSL
            //2.1 query
            buildBasicQuery(params,request);
            //2.2分页
            int page = params.getPage();
            int size = params.getSize();
            request.source().from((page-1)*size).size(size);
            //2.3地理位置排序
            String location = params.getLocation();
            if(location!=null && !"".equals(location)){
                request.source().sort(SortBuilders
                        .geoDistanceSort("location",new GeoPoint(location))
                        .order(SortOrder.ASC)
                        .unit(DistanceUnit.KILOMETERS)
                );
            }
            //2.4高亮
            request.source().highlighter(new HighlightBuilder()
                    .field("name")
                    .requireFieldMatch(false));
            //3.发送请求
            SearchResponse response = client.search(request, RequestOptions.DEFAULT);
            //4.解析响应
            return handleResponse(response);
        }catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 封装基础查询
     *
     * */
    private void buildBasicQuery(RequestParams params, SearchRequest request){
        // 1.构建BooleanQuery
        BoolQueryBuilder boolQuery = QueryBuilders.boolQuery();
        // 2.关键词搜索
        String key = params.getKey();
        /**
         * 搜索关键词不存在就全部查询
         * 否则按照关键词搜索
         * */
        if (key == null || "".equals(key)) {
            boolQuery.must(QueryBuilders.matchAllQuery());
        } else {
            boolQuery.must(QueryBuilders.matchQuery("all", key));
        }
        //3.城市条件,如果城市不为空，则拼上城市的bool条件
        if(params.getCity()!=null && !"".equals(params.getCity())){
            boolQuery.filter(QueryBuilders.termQuery("city",params.getCity()));
        }
        //4.品牌条件
        if(params.getBrand()!=null && !"".equals(params.getBrand())){
            boolQuery.filter(QueryBuilders.termQuery("brand",params.getBrand()));
        }
        // 5.星级条件
        if (params.getStarName() != null && !"".equals(params.getStarName())) {
            boolQuery.filter(QueryBuilders.termQuery("starName", params.getStarName()));
        }
        // 6.价格
        if (params.getMinPrice() != null && params.getMaxPrice() != null) {
            boolQuery.filter(QueryBuilders
                    .rangeQuery("price")
                    .gte(params.getMinPrice())
                    .lte(params.getMaxPrice()));
        }
        // 7.算分控制
        FunctionScoreQueryBuilder functionScoreQueryBuilder = QueryBuilders.functionScoreQuery(
                // 原始查询，相关性算分的查询
                boolQuery,
                // function score的数组
                new FunctionScoreQueryBuilder.FilterFunctionBuilder[]{
                        // 其中的一个function score 元素
                        new FunctionScoreQueryBuilder.FilterFunctionBuilder(
                                //过滤条件
                                QueryBuilders.termQuery("isAD", true),
                                // 算分函数
                                ScoreFunctionBuilders.weightFactorFunction(10)
                        )
        });
        // 8.放入source
        request.source().query(functionScoreQueryBuilder);

    }

    /**
     * 结果解析
     * */
    private PageResult handleResponse(SearchResponse response) {
        // 4.解析响应
        SearchHits searchHits = response.getHits();
        // 4.1.获取总条数
        long total = searchHits.getTotalHits().value;
        // 4.2.文档数组
        SearchHit[] hits = searchHits.getHits();
        // 4.3.遍历
        List<HotelDoc> hotels = new ArrayList<>();
        for (SearchHit hit : hits) {
            // 获取文档source
            String json = hit.getSourceAsString();
            // 反序列化
            HotelDoc hotelDoc = JSON.parseObject(json, HotelDoc.class);
            // 获取排序值
            Object[] sortValues = hit.getSortValues();
            if(sortValues.length > 0){
                Object sortValue = sortValues[0];
                hotelDoc.setDistance(sortValue);
            }
            // 获取高亮结果
            Map<String, HighlightField> highlightFields = hit.getHighlightFields();
            if (highlightFields!=null && highlightFields.size() > 0) {
                // 根据字段名获取高亮结果
                HighlightField highlightField = highlightFields.get("name");
                if (highlightField != null) {
                    // 获取高亮值
                    String name = highlightField.getFragments()[0].string();
                    // 覆盖非高亮结果
                    hotelDoc.setName(name);
                }
            }
            // 放入集合
            hotels.add(hotelDoc);
        }
        // 4.4.封装返回
        return new PageResult(total, hotels);
    }
}
